Sheffield United have suspended striker Jose Baxter for the second time in nine months.
The Blades have not specified why they have taken the action against the 24-year-old, a former Everton trainee.
A brief club statement said: "Procedures are being followed and no further comment will be made until the completion of these actions."
Baxter joined the club from Oldham Athletic in 2013, and has scored 20 goals in 93 league appearances.
He was handed a five-month suspension, with the final three of those suspended, by the Football Association in July after failing an out-of-competition drugs test in May.
The player denied any intentional wrongdoing in a personal hearing, adding the traces of ecstasy found in his system were as a result of his drink being spiked.